National surveys reveal that alcohol is by far the most commonly used drug among young persons, with approximately 50 percent of these youths reporting having consumed it at some time. Marijuana is the next most commonly used drug, followed at much smaller frequencies by cocaine, stimulants, sedatives, hallucinogens, and heroin. Prevalence data indicate that the majority of these youths do not become regular users. Substance use ordinarily starts with drinking beer and wine, drinking hard liquor, smoking marijuana, and using other drugs. Certain personal, social, and family factors are associated with drug use, and the youths with major drug abuse problems often also have a psychological disorder. Successful intervention requires a multifaceted approach that is tailored to the specific pattern of drug abuse. Prevention efforts have shifted from merely providing information or general social skills to a focus specifically on training youths to cope effectively with the determinants of drug abuse. Case examples and 82 references